Finiteness of toric H^1 in a Laurent module
OpenOAI.MaximalSeshadri.PlaneCech.toric_H1_finitemaximal-seshadrioai-math
With and clearing as above, let be -submodules of stable under coneA, coneB and coneC 0, containing respectively and generated over those cones by . Then the quotient of cycles A B C (triples in summing to zero) by vertexBoundaries A B C V is finite over .
Notation. cycles A B C is the submodule of of triples with zero sum.
Formalization Note The statement is verbatim from OpenAI's Lean development, with Definitions files of this development imported in place of the upstream modules; these are supporting code for the statement.
Preamble
import Mathlib
import Definitions.Def_MaximalSeshadriConstants
import Definitions.Def_SeshadriPrelim6
namespace OAI
section
namespace MaximalSeshadri.PlaneCech
noncomputable section
open LaurentPlane
variable {K M : Type*} [Field K] [AddCommGroup M]
[Module K M]
variable [Module (LaurentPlane.Ring K) M] [IsScalarTower K (LaurentPlane.Ring K) M]
Formal statement
theorem toric_H1_finite (V : Fin 3 → Submodule K M)
(stable : ∀ i z, z ∈ vertexCone i → ∀ x ∈ V i, T (K := K) z • x ∈ V i)
{ι : Fin 3 → Type*} [∀ i, Fintype (ι i)] (g : ∀ i, ι i → M)
(hg : ∀ i a, g i a ∈ V i)
(clear : ∀ i j (x : M), x ∈ V j →
∃ d : ℕ, T (K := K) (d • (weight j-weight i)) • x ∈ V i)
(A B C : Submodule K M)
(hA : ∀ z ∈ coneA, ∀ x ∈ A, T (K := K) z • x ∈ A)
(hB : ∀ z ∈ coneB, ∀ x ∈ B, T (K := K) z • x ∈ B)
(hC : ∀ z ∈ coneC 0, ∀ x ∈ C, T (K := K) z • x ∈ C)
(incA : V 0 ≤ A) (incB : V 0 ≤ B) (incC : V 1 ≤ C)
(genA : A = monomialSpan (K := K) coneA (g 0)) (genB : B = monomialSpan (K := K) coneB (g 0))
(genC : C = monomialSpan (K := K) (coneC 0) (g 1)) :
Module.Finite K ((cycles A B C) ⧸ vertexBoundaries A B C V) := by
sorry
end
end MaximalSeshadri.PlaneCech
end
end OAI
Source
OpenAI, Maximal Seshadri constants on arbitrary polarized surfaces, September 23, 2026, https://github.com/openai/math (paper: preprints/Maximal-Seshadri-Constants-on-Arbitrary-Polarized-Surfaces-September-23-2026/main.pdf; Lean: lean/OAI/AlgebraicGeometry/Seshadri, Apache License 2.0); Lean declaration `OAI.MaximalSeshadri.PlaneCech.toric_H1_finite`, https://github.com/openai/math/blob/adc7f1241b42e322a6451854ab7e4b4c146bf78a/lean/OAI/AlgebraicGeometry/Seshadri/Cohomology/ToricH1.lean#L82